Cod sursa(job #1751626)

Utilizator MihalachiRazvanMihalachi Razvan MihalachiRazvan Data 1 septembrie 2016 17:49:09
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.35 kb
Raporteaza aceasta sursa 
#include <fstream>
#include <iostream>
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
 char sir[2000001];
 long long int n,i,j,k=1;
int main()
{

   fin>>n;
for(i=3;i<=n;i=i+2)
   {
       if(sir[i]==0)
       {k++;
        for(j=i*3;j<=n;j=j+i*2)
            sir[j]=1;}

   }
   fout<<k;

    return 0;
}